Comonotone additivity for two price economy bid and ask prices motivates combining bid prices for call options with the ask prices for puts and the converse to construct two densities (termed lower and upper) reflected by these prices. The two densities scaled to a unit mean are here linked by...

The bilateral gamma model for returns is naturally derived from the lognormal model. Maximizing entropy in a random time change delivers the symmetric variance gamma model. The asymmetric variance gamma follows on incorporating skewness. Differential speeds for the upward and downward motions...

Market efficiency is measured by arbitrage proximity. The magnitude of probability distortion necessary to remove drift calibrates the efficiency. Simulations of bilateral gamma models estimated on a year's past returns yield empirical acceptability indices for each day for each asset. The...

Comonotone additivity for two price economy bid and ask prices motivates combining bid prices for call options with the ask prices for puts and the converse to construct two densities (termed lower and upper) reflected by these prices. Bilateral gamma models are fit to estimate these the lower...

The risk conscious investor is defined as the maximizer of a conservative valuation or dynamically a nonlinear expectation. Both the static and dynamic problems are addressed using distortions of tail probabilities or distortions of tail measures. The multivariate static problem is solved in the...

Nonlinear martingale theory is used to form lower and upper price processes straddling a martingale. The martingale return is then modeled in terms of risk charges associated with the returns on the straddling lower and upper processes. The move to physically expected returns is made via the...